Add throwExceptionIfClosed(); to most public methods for classes implementing Closeable, https://github.com/OpenHFT/Chronicle-Core/issues/116

src/main/java/net/openhft/chronicle/map/MapClosable.java

@@ -6,6 +6,7 @@ public interface MapClosable extends Closeable {
 
     @Override
     default boolean isClosed() {
-        throw new UnsupportedOperationException();
+        // if we don't know, pretend it is not.
+        return false;
     }
 }